mculloch 1-43 wont stay running

[andyb]

I got an old 1-43 recently and its being quite stubborn. it will fire but wont stay going for very long at all. I put in a new carb kit, checked spark, but compression is only 75 lbs. That seems awful low but this is my first old mac and cant find much data on it. I have the carb at factory settings, L 3/4 turn, H 1 1/2 turn. Have tried tuning with no luck. fuel is 20:1 mix. fuel lines seem in good shape but new ones are on order anyways. maybe a vacuum leak somewhere?

 

[heimannm]

If the compression is really only 75 PSI it likely will not run. Even the old reed saws need to be over 90 to run at all.

Make sure your compression gauge has a Schrader valve at the tip to get an accurate reading. If it really is 75 PSI you will need to evaluate the saw more thoroughly to decide if it is worth pursuing repairs.

All that said, try setting both H and L around 1-1/4 to 1-12 turns open and give it a try. 3/4 on the low is probably not enough fuel to sustain idle.

Mark

 

[andyb]

It is a schrader valve tester. I checked the reeds today too and they are fine. Unfortunately she might be a display piece… looked in the crank case with the reeds off and lots of gunk in the bottom. Sounds like more trouble than its worth. With that said anyone with and old mac for sale I would love and old mac to actually run and put to work.